Recently, numerous researchers have been mainly focused on the development of nanoelectronics especially for its applications on nanosystems or devices. Engineers attempted to minimize not only conventional circuit elements like transistors but also the entire integrated circuit including memory storage units. One of the key challenges for achieving nanodevices is to enable low resistance electrical contacts and reproducible connections between electrodes whose width of the gap is often in nanometer scales. Such nanodevices often use carbon nanotubes (CNTs), nanowires (NWs), or quantum dots (QDs) as the interconnecting material because of their unique electrical and thermal properties. The ballistic transport in CNTs and NWs makes carriers suffering no scattering event even at room temperature, compared to other semi-conducting materials. Due to the direct band gap property, CNTs also play an important role in optoelectronics, and act as an essential element for both optical detection and optical emission. Thus, many papers are published on examining different properties of individual CNT under different conditions so as to explore more applications.
Current methods in making CNT or NW connections includes direct CNT and NW growth across electrodes, deposition of as-grown CNTs or NWs on electrodes by dielectrophoresis, fabrication of electrodes on top of as-deposited CNTs or NWs either by electron-beam (E-beam) lithography or shadow masks, and self-assembly by functionalizing CNTs or NWs and electrodes with different chemicals or even DNA molecules. To a certain extent, these methods have their shortcomings in terms of repeatability and ability in eliminating uncertainties. Thus, it is highly desired to have a reliable and repeatable way to form CNT or NW electrical connection across electrodes.